Spotted lanternflies are an invasive planthopper species that originated in Asia and were first identified in the United States in Pennsylvania in 2014. These insects pose a significant threat to a wide variety of plants, including fruit trees, grapevines, and various hardwood and ornamental trees. They cause damage by piercing plant tissues and extracting sap, which can weaken the host plant and stunt its growth. As they feed, spotted lanternflies excrete a sugary substance called honeydew, which promotes the growth of black sooty mold on affected plants and surfaces. This sticky residue can also attract other insects and lead to substantial economic losses in agricultural and forestry industries.
Hatching Season and Environmental Cues
Spotted lanternfly eggs begin to hatch in the spring. This hatching period spans from late April through June, though timing can vary depending on geographic location and local climate conditions. Rising temperatures in the spring serve as the primary environmental cue that triggers the eggs to hatch.
The emergence of nymphs from egg masses does not occur all at once but can unfold over several weeks. Vigilance is necessary throughout this extended hatching period. Understanding this timeframe allows for proactive measures to manage their populations as the weather warms.
Appearance of Eggs and Newly Hatched Nymphs
Spotted lanternfly egg masses are laid from September through December and can be found on nearly any hard surface, including tree trunks, rocks, outdoor furniture, vehicles, and even building materials. These masses are about 1 to 1.5 inches long and initially appear as greyish, mud-like patches. A waxy coating covers the eggs, which may appear smooth and shiny when first laid but dries over time, turning dull and brown, often developing cracks that resemble dried mud. Each egg mass can contain between 30 to 60 eggs arranged in rows.
Once hatched, nymphs are in their first instar stage. These young insects measure approximately 1/8 to 1/4 inch in length. They are characterized by their black bodies with distinct white spots and may resemble small ticks. First instar nymphs are active from May through July and are strong jumpers, capable of moving quickly to find host plants.
Taking Action When They Hatch
Identifying and addressing spotted lanternfly egg masses before they hatch is an effective way to reduce future populations. If egg masses are found, they can be scraped off the surface using a stiff tool like a credit card or putty knife. It is important to scrape the egg masses into a re-sealable bag or container filled with rubbing alcohol or hand sanitizer to ensure the eggs are destroyed. The bag should then be sealed and properly discarded.
For newly hatched nymphs, immediate action can also help manage their numbers. Nymphs can be physically crushed or stomped on. Another approach involves using sticky bands wrapped around tree trunks, which are effective at trapping the nymphs as they climb up and down the trees. When using sticky bands, it is important to take precautions to prevent non-target animals, such as birds or small mammals, from getting caught. This can be achieved by placing a wildlife barrier around the sticky band or by selecting bands with inward-facing adhesive.